Applicant hereby claims foreign priority benefits under 35 U.S.C. xc2xa7 119 of PCT Application No. CH00/00202, filed Apr. 6, 2000, the disclosure of which is herein incorporated by reference.
The invention relates to a method and apparatus for forming metal sheets into taper tube shells.
Taper tubes are desired for a multitude of applications. However, taper tube shells that can subsequently be welded to make a taper tube are expensive to fabricate.
Therefore the fundamental problem of the invention is to offer a simple way of rounding sheets conically.
This problem is solved in the case of a method of the kind stated at the outset, by employing a conical die and punch to deform an individual sheet. Initially the sheet is laid on the length of the die at the start of pressing, and the punch executes a curvilinear motion on plunging into the die.
Also the problem is solved in the case of an apparatus of the kind stated at the outset, by a matching conical punch and die set with actuating means by which the punch is insertable along a curved path into the die.